Assemblies should explicitly state their CLS compliance using the CLSCompliant attribute. An assembly without this attribute ...

Assemblies should explicitly state their CLS compliance using the CLSCompliant attribute. An assembly without this attribute is not CLS-compliant. Assemblies, modules, and types can be CLS-compliant even if some parts of the assembly, module, or type are not CLS-compliant. The following rules apply: 1) If the element is marked CLSCompliant, any noncompliant members must have the CLSCompliant attribute present with its argument set to false. 2) A comparable CLS-compliant alternative member must be supplied for each member that is not CLS-compliant.